Levoglucosan-based flame retardant compounds

ABSTRACT

A levoglucosan-based flame retardant compound, a process for forming a flame retardant polymer, and an article of manufacture comprising a polymer that contains the levoglucosan-based flame retardant compound. The levoglucosan-based flame retardant compound has phosphorus-based flame retardant functional groups. At least one of the phosphorus-based flame retardant groups includes a phenyl substituent. The process for forming the flame retardant polymer includes providing a phosphorus-based flame retardant molecule, providing levoglucosan, chemically reacting the phosphorus-based flame retardant molecule and the levoglucosan derivative to form a levoglucosan-based flame retardant compound, and incorporating the levoglucosan-based flame retardant compound into a polymer by covalent binding to form the levoglucosan-based flame retardant polymer.

BACKGROUND

The present disclosure relates to bio-renewable flame retardantcompounds and, more specifically, levoglucosan-based flame retardantcompounds.

Bio-based, sustainable compounds can be used in the syntheses ofsubstances that previously required petroleum-based raw materials.Examples of uses for bio-based compounds include polymers, flameretardants, cross-linkers, etc. There are numerous strategies forefficiently and inexpensively producing bio-based compounds on anindustrial scale. Examples of these strategies can be found infermentation technologies, membrane technologies, and geneticengineering. Levoglucosan (6,8-dioxabicyclo[3.2.1]octane-2,3,4-triol) isone example of a bio-based compound. Levoglucosan is produced bypyrolysis of carbohydrates.

SUMMARY

Various embodiments are directed to levoglucosan-based flame retardantcompounds. The levoglucosan-based flame retardant compounds havephosphorus-based flame retardant groups, wherein at least one of whichhas a phenyl substituent. The flame retardant groups can also include anadditional phenyl substituent or a reactive functional group. Reactivefunctional groups can include allyl groups, epoxy groups, propylenecarbonate groups, amino groups, carboxylic acid groups, and hydroxylgroups. Further, the flame retardant groups can include phosphonyland/or phosphoryl moieties. The levoglucosan-based flame retardantcompounds can be incorporated into a polymer to form a flame retardantpolymer.

Additional embodiments are directed to a process of forming alevoglucosan-based flame retardant polymer. The levoglucosan-based flameretardant polymer can be produced by providing a phosphorus-based flameretardant molecule, providing levoglucosan, which can have one or moreprotecting groups, chemically reacting the phosphorus-based flameretardant molecule and the levoglucosan to form a levoglucosan-basedflame retardant compound, and incorporating the levoglucosan-based flameretardant compound into a polymer by covalent binding to form the flameretardant polymer. The levoglucosan can come from a bio-based source.The phosphorus-based flame retardant molecule can be a phosphorus-basedcompound with allyl, epoxy, or phenyl groups. The levoglucosan-basedflame retardant compound can have at least one functional group such asan allyl group, an epoxy group, a propylene carbonate group, acarboxylic acid group, an amine group, or a hydroxyl group.Additionally, the levoglucosan-based flame retardant compound can beincorporated into the polymer by cross-linking or polymerization.

Further embodiments are directed to an article of manufacture comprisinga material that contains a polymer into which a levoglucosan-based flameretardant compound has been incorporated. The levoglucosan-based flameretardant compound has phosphorus-based flame retardant groups, whereinat least one of which has a phenyl substituent. The article ofmanufacture can also contain an electronic component. Additionally, thematerial containing the levoglucosan-based flame retardant polymer canbe a plastic for integrated circuit packing or an adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram illustrating a process of forming a flameretardant polymer containing a levoglucosan-based flame retardantpolymer.

FIG. 2 is a diagrammatic representation of the molecular structures oflevoglucosan, functionalized phosphorus-based flame retardant molecules,and phenyl-substituted phosphorus-based flame retardant molecules.

FIG. 3A is a chemical reaction diagram illustrating two processes ofsynthesizing an R¹-functionalized phosphate-based flame retardantmolecule, according to some embodiments of the present disclosure.

FIG. 3B is a chemical reaction diagram illustrating two processes ofsynthesizing an R¹-functionalized phosphonate-based flame retardantmolecule, according to some embodiments of the present disclosure.

FIG. 3C is a chemical reaction diagram illustrating a process ofsynthesizing a carboxylic acid-derived phenyl-substituted flameretardant thiol molecule and a process of synthesizing a hydroxy-derivedphenyl-substituted flame retardant thiol molecule, according to someembodiments of the present disclosure.

FIG. 3D is a chemical reaction diagram illustrating a process ofsynthesizing an amine-derived phenyl-substituted flame retardant thiolmolecule, according to some embodiments of the present disclosure.

FIG. 3E is a diagrammatic representation of the molecular structures ofthree thiol molecules that are involved in the synthesis of thelevoglucosan-based compounds, according to some embodiments of thepresent disclosure.

FIG. 4 is chemical reaction diagram illustrating processes ofsynthesizing a di-protected levoglucosan derivative and a mono-protectedlevoglucosan derivative, according to some embodiments of the presentdisclosure.

FIG. 5A is a chemical reaction diagram illustrating processes of formingan R¹-trifunctionalized levoglucosan-based flame retardant compound anda phenyl-substituted levoglucosan-based flame retardant compound,according to some embodiments of the present disclosure.

FIG. 5B is a chemical reaction diagram illustrating processes of formingan R¹(2)-monofunctionalized levoglucosan-based flame retardant compoundand an R¹(1,3)-difunctionalized levoglucosan-based flame retardantcompound, according to some embodiments of the present disclosure.

FIG. 5C is a chemical reaction diagram illustrating processes of formingan R¹(2,3)-difunctionalized levoglucosan-based flame retardant compoundand an R¹(1)-monofunctionalized levoglucosan-based flame retardantcompound, according to some embodiments of the present disclosure.

FIG. 5D is a chemical reaction diagram illustrating a process of formingan R²-trifunctionalized levoglucosan-based flame retardant compound,according to some embodiments of the present disclosure.

FIG. 5E is a chemical reaction diagram illustrating a process of formingphenyl-substituted E¹ thioether-linked levoglucosan-based flameretardant compounds, according to some embodiments of the presentdisclosure.

FIG. 5F is a chemical reaction diagram illustrating a process of formingtrifunctionalized E² thioether-linked levoglucosan-based flame retardantcompounds, according to some embodiments of the present disclosure.

FIG. 6 is a diagrammatic representation of a generic levoglucosan-basedflame retardant compound.

FIG. 7A is a diagrammatic representation of the structures of generic R¹or R²-functionalized levoglucosan-based flame retardant monomers,according to some embodiments of the present disclosure.

FIG. 7B is a chemical reaction diagram illustrating processes ofsynthesizing levoglucosan-based flame retardant polymers fromlevoglucosan-based flame retardant compounds, according to someembodiments of the present disclosure.

DETAILED DESCRIPTION

Bio-based compounds are increasingly being used in the syntheses ofsubstances that previously required petroleum-based raw materials. Onebenefit of bio-based compounds is that they are from renewableresources. Therefore, these compounds have applications in sustainable,or “green,” materials. Sustainable materials are becoming more and moreprevalent, due to the rising costs of fossil fuels and increasingenvironmental regulatory controls. Advances in biotechnology haveprovided numerous strategies for efficiently and inexpensively producingbio-based compounds on an industrial scale. Examples of these strategiescan be found in fermentation technologies, membrane technologies, andgenetic engineering. Biotechnological strategies can include plant-basedand microorganism-based approaches. Plant-based approaches can involveobtaining a material directly from a plant, or growing plant tissues orcells that can produce bio-based compounds from various substrates usingtheir own biosynthetic pathways. Microorganism-based approaches involveusing native or genetically modified fungi, yeast, or bacteria toproduce a desired compound from a structurally similar substrate.

Examples of uses for bio-based compounds include polymers, flameretardants, cross-linkers, etc. In some examples, bio-based polymers andpetroleum-based polymers are blended to form a polymer composite.However, polymers can also be entirely bio-based, or produced from acombination of bio- and petroleum-based monomers. Bio-based compoundscan impart flame retardant properties to bio- and petroleum-basedpolymers. For example, flame retardant molecules or cross-linkers can beincorporated into polymers. Additionally, flame retardant monomers canbe polymerized to form flame retardant polymers. Levoglucosan(6,8-dioxabicyclo[3.2.1]octane-2,3,4-triol) is one example of abio-based compound that can have applications as a component of variouspolymers, resins, and monomers. Levoglucosan is obtained from thepyrolysis of carbohydrates, such as starch and cellulose.

According to the present disclosure, levoglucosan is used as a precursorfor flame retardant compounds. These compounds can include smallmolecules, cross-linkers, monofunctional molecules, and monomers. Thelevoglucosan-based flame retardant compounds can be added to polymers,fabrics, resins, or other materials during blending, curing, foaming,extrusion, or other processing techniques. In addition to directlyadding the levoglucosan-based flame retardant monomers to the materialsduring processing, the added levoglucosan-based flame retardant monomerscan be contained within microcapsules.

FIG. 1 is a flow diagram illustrating a process 100 of forming a flameretardant polymer containing a levoglucosan-based flame retardantpolymer. Process 100 begins with the obtainment of a phosphorus-basedflame retardant molecule. This is illustrated at step 104. Thephosphorus-based flame retardant molecule has either a phosphoryl or aphosphonyl moiety (collectively referred to as an FR group) with aphenyl (Ph) group and a functional group or second phenyl group. Thefunctional groups are reactive groups involved in polymerization orbinding to polymer chains. These functional groups can vary, as isdiscussed in greater detail below. The phosphorus-based flame retardantmolecules can be phosphate- or phosphonate-based flame retardantmolecules. The phosphorus-based flame retardant molecules can besynthesized as needed, or obtained from a commercial source. Thestructures and syntheses of phosphorus-based flame retardant moleculesare discussed in greater detail with respect to FIGS. 2 and 3A-3D.

Process 100 continues with the provision of levoglucosan. This isillustrated at step 108. Levoglucosan is formed from the pyrolysis ofcarbohydrates, such as starch and cellulose, and can be obtained from acommercial source. Levoglucosan has a six-carbon ring structure, andincludes three hydroxyl groups per ring. In some embodiments, protectinggroups are attached at one or two of the three hydroxyl groups. Examplesof reactions to attach these protecting groups are discussed in greaterdetail with respect to FIG. 4. It should be noted that the provision oflevoglucosan in step 108 is illustrated as occurring after the formationof the phosphorus-based flame retardant molecule in step 104. However,in some embodiments, step 108 can occur before step 104. Further, steps104 and 108 can occur simultaneously in some embodiments.

The protected or unprotected levoglucosan and the phosphorus-based flameretardant molecule are chemically reacted in order to form alevoglucosan-based flame retardant compound. This is illustrated at step112. The identity of the levoglucosan-based flame retardant compound isdetermined by the levoglucosan (i.e., protected or unprotected) and thephosphorus-based flame retardant molecule used in the reaction. The FRgroups of the phosphorus-based flame retardant compound are bonded tohydroxyl and/or carboxylic acid groups on the levoglucosan in a reactionwith levoglucosan and the phosphorus-based flame retardant compounds.Additionally, in some embodiments, modifications to the FR groups (e.g.,forming or attaching new functional groups) are made after binding tothe levoglucosan. The syntheses and structures of levoglucosan-basedflame retardant compounds are discussed in greater detail with respectto FIGS. 5A-5F.

The levoglucosan-based flame retardant compound formed in step 112 ispolymerized, or added to another polymer, yielding a levoglucosan-basedflame retardant polymer. This is illustrated at step 116. Thelevoglucosan-based flame retardant compounds can be added to a polymeras small molecules, cross-linkers, or bound monofunctional molecules.This addition can involve chemical crosslinking, mixing, blending,forming a matrix, forming a composite polymer, etc. The addition of thelevoglucosan-based flame retardant compounds to the polymers can occurduring blending, curing, foaming, extrusion, or other processingtechniques. Further, the levoglucosan-based flame retardant compoundscan be polymerized in a reaction with a base and/or a second monomer.Additionally, in some embodiments, the levoglucosan-based flameretardant compound can self-polymerize, or be polymerized in a reactionwith a Ziegler-Natta catalyst. Polymerization reactions with thelevoglucosan-based flame retardant compounds are discussed in greaterdetail with respect to FIG. 7B.

FIG. 2 is a diagrammatic representation of the molecular structures 200of levoglucosan 202, functionalized phosphorus-based flame retardantmolecules 204-1 and 204-2 (referred to collectively as 204) andphenyl-substituted phosphorus-based flame retardant molecules 206-1 and206-2 (referred to collectively as 206), according to some embodimentsof the present disclosure. Herein, the locations of three hydroxylgroups on levoglucosan and its derivatives are referred to from top tobottom as the first position, second position, and third position. Thesepositions are given the numbers 1, 2, and 3, respectively, in FIG. 2.

Each phosphorus-based flame retardant molecule is either aphosphate-based flame retardant molecule 204-1 and 206-1 orphosphonate-based flame retardant molecule 204-2 and 206-2. Herein,phosphoryl and phosphonyl moieties in the phosphate- andphosphonate-based compounds, respectively, are replaced by theabbreviation “FR” in order to simplify illustrations of the molecularstructures. The moieties replaced by the abbreviation each have a phenylsubstituent. However, this phenyl can be replaced by another alkylsubstituent (e.g., methyl, ethyl, propyl, isopropyl, etc.).

The compounds referred to as phenyl-substituted flame retardantphosphorus-based flame retardant molecules 206, each have two phenyl(Ph) substituents. The compounds referred to as R¹-functionalizedphosphorus-based flame retardant molecules 204 each have an R¹functional group in addition to a single phenyl (Ph) substituent. Insome embodiments, the phenyl substituents are replaced by another alkylsubstituent (e.g., methyl, ethyl, propyl, isopropyl, etc.). Examplesyntheses of the R¹-functionalized phosphorus-based flame retardantmolecules 204, as well as examples of R¹ functional groups, arediscussed with respect to FIGS. 3A and 3B. The phosphorus-based flameretardant molecules 204 and 206 are reacted with levoglucosan orlevoglucosan derivatives to form levoglucosan-based flame retardantcompounds. Modifications to the R¹ groups made in additional reactionsthat are carried out after the phosphorus-based compounds 204 and 206are bound to the levoglucosan 202 result in groups referred to as R²,E¹, and E² herein. These reactions are discussed in greater detail withrespect to FIGS. 5C-5F.

Herein, levoglucosan-based flame retardant compounds are referred to asfunctionalized (monofunctionalized, difunctionalized, ortrifunctionalized) or phenyl-substituted. Terminal functional groupsattached to FR moieties (e.g., allyl, epoxy, propylene carbonate, amino,carboxylic acid, and hydroxyl groups) are involved in binding to polymerchains and/or polymerization reactions, while the phenyl substituents onthe FR moieties do not participate in these reactions. Therefore, anycompound with at least one functional group is referred to asfunctionalized to indicate that it will participate in binding orpolymerization. Levoglucosan-based flame retardant compounds with onlyphenyl-substituents on their FR moieties are small molecules that causea polymer to be flame retardant when blended into the polymer.

FIG. 3A is a chemical reaction diagram illustrating two processes 300-1and 300-2 of synthesizing an R¹-functionalized phosphate-based flameretardant molecule 204-1, according to some embodiments of the presentdisclosure. In both processes 300-1 and 300-2, an alcohol 304 is astarting material for the R¹-functionalized phosphate-based flameretardant molecule 204-1. The alcohol 304 has either an allyl R¹ group306 or an epoxy R¹ group 307. It should be noted that, though R¹ groupswith single methylene bridge groups are illustrated here, other alcoholswith chains of varying lengths (e.g., one to twelve methylene bridgegroups) could be used. Additionally, alcohols with acrylate substituentsare used in some embodiments.

In process 300-1, the alcohol 304 is reacted with diphenyl phosphite andtitanium isopropoxide (Ti(O^(i)Pr)₄) in benzene to produce a precursor308 to the R¹-functionalized phosphate-based flame retardant molecule204-1. In this pseudo-transesterification reaction, the precursor 308 isformed when a phenyl (Ph) substituent on diphenyl phosphite is replacedby the R¹ group from the alcohol 304. The precursor 308 is then reactedwith thionyl chloride (SOCl₂) and carbon tetrachloride (CCl₄) over arange of approximately 0° C. to room temperature (RT, e.g., 15-25° C.),forming the R¹-functionalized phosphate-based flame retardant molecule204-1. In process 300-2, the alcohol 304 is reacted with phenyldichlorophosphate in a tetrahydrofuran (THF) solution containingtriethylamine (Et₃N). This process is carried out over a range ofapproximately 0° C. to room temperature (RT, e.g., 15-25° C.). Achloride on the phenyl dichlorophosphate is replaced by the alcohol 304,forming the R¹-functionalized phosphate-based flame retardant molecule204-1.

FIG. 3B is a chemical reaction diagram illustrating two processes 300-3and 300-4 of synthesizing an R¹-functionalized phosphonate-based flameretardant molecule 204-2, according to some embodiments of the presentdisclosure. In both processes 300-3 and 300-4, an organochloride 312 isa starting material for the R-functionalized phosphonate-based flameretardant molecule 204-2. The organochloride has either an allyl R¹group 306 or an epoxy R¹ group 307. It should be noted that, as in thecase of the alcohol 304, organochlorides with chains of varying lengths(e.g., one to twelve methylene bridge groups) could be used.Additionally, organochlorides with acrylate substituents are used insome embodiments.

In process 300-3, the organochloride 312 is reacted with triphenylphosphite (P(OPh)₃). The mixture is heated, either by refluxing intoluene or microwaving (mw) in ethanol (EtOH), producing a phosphonylester precursor 316 to the R¹-functionalized phosphonate-based flameretardant molecule 204-2. The phosphonyl ester precursor 316 is reactedwith phosphorus pentachloride (PCl₅S) to form the R¹-functionalizedphosphonate-based flame retardant molecule 204-2.

In process 300-4, a mixture of the organochloride 312 and triphenylphosphite (P(OPh)₃) is heated, either by refluxing in toluene ormicrowaving (mw) in ethanol (EtOH), forming a phenylphosphinic acidprecursor 320 to the R¹-functionalized phosphonate-based flame retardantmolecule 204-2. The reaction is then quenched by raising the pH of thesolution. In this example, an ethanol (EtOH)/water (H₂O) solution ofsodium hydroxide (NaOH) is added to the reaction mixture. However, insome embodiments, bases other than sodium hydroxide, such as potassiumhydroxide or lithium hydroxide, are used to quench the reaction. Whenthe reaction has been quenched, thionyl chloride (SOCl₂) is added to thephenylphosphinic acid precursor 320, producing the R¹-functionalizedphosphonate-based flame retardant molecule 204-2.

FIG. 3C is a chemical reaction diagram illustrating a process 300-5 ofsynthesizing a carboxylic acid-derived phenyl-substituted flameretardant thiol molecule 328 and a process 300-6 of synthesizing ahydroxy-derived phenyl-substituted flame retardant thiol molecule 336,according to some embodiments of the present disclosure. In process300-5, acetate-protected thiopropionic acid 324 is reacted withmagnesium oxide (MgO) and a phenyl-substituted phosphorus-based flameretardant compound 206. The acetate group is then removed by refluxingthe mixture in an ethanol (EtOH) solution containing sodium hydroxide(NaOH), yielding the carboxylic acid-derived phenyl-substituted flameretardant thiol molecule 328.

In process 300-6, an alcohol 304 with an allyl R group 306 is reactedwith thioacetic acid in a thiol-ene reaction. In the first step of thereaction, oxygen (O₂) is added to a dichloromethane (DCM) solution ofthe allyl alcohol 304 and thioacetic acid. The mixture is refluxed,resulting in an acetate-protected mercaptopropanol 332. The second stepin the reaction is a substitution reaction involving aphenyl-substituted phosphorus-based flame retardant compound 206,catalytic dimethylaminopyridine (cat. DMAP), and/or a stoichiometricamount of an organic amine, such as triethylamine. The acetate group isremoved by refluxing the mixture in an ethanol (EtOH) solutioncontaining sodium hydroxide (NaOH). This step results in the productionof the hydroxy-derived phenyl-substituted flame retardant thiol molecule336.

FIG. 3D is a chemical reaction diagram illustrating a process 300-7 ofsynthesizing an amine-derived phenyl-substituted flame retardant thiolmolecule 348, according to some embodiments of the present disclosure.In process 300-7, 1-(boc-amino)-3-butene 340 is first reacted withthioacetic acid in a thiol-ene reaction. Azobisisobutyronitrile (AIBN)is added to the dioxane solution of 1-(boc-amino)-3-butene 340 andthioacetic acid, and the mixture is stirred at 75° C., resulting in anacetate-protected precursor 344 to the amine-derived phenyl-substitutedflame retardant thiol molecule 348. The second step in process 300-7 isa substitution reaction with a phenyl-substituted phosphorus-based flameretardant compound 206, catalytic dimethylaminopyridine (cat. DMAP),and/or a stoichiometric amount of an organic amine, such astriethylamine. The acetate group and boc groups are removed under basicconditions (e.g., by refluxing the mixture in an ethanol (EtOH) solutioncontaining sodium hydroxide (NaOH)). This step results in the productionof the amine-derived phenyl-substituted flame retardant thiol molecule348.

Each of the thiols produced in processes 300-5, 300-6, and 300-7 canprovide phenyl-substituted thioether groups in the syntheses ofE¹-functionalized thioether-linked levoglucosan-based flame retardantcompounds. These reactions are discussed in greater detail with respectto FIG. 5E. If processes 300-5, 300-6, and 300-7 are carried out with206-1, the resulting phenyl-substituted flame retardant thiol molecules328, 336, and 348, respectively, will have phosphoryl FR groups, and, ifthe reactions are carried out with 206-2, the resultingphenyl-substituted flame retardant thiol molecules 328, 336, and 348will have phosphonyl FR groups. Further, it should be noted thatprocesses 300-5, 300-6, and 300-7 can be carried out with theR¹-functionalized phosphorus-based flame retardants 204, resulting inthiol molecules with R¹ functional groups. The R¹ functional groupsattached to thiol groups that have been bound to levoglucosan canparticipate in any of the reactions illustrated below that involve R¹functional groups and their derivatives, though these reactions are notshown.

FIG. 3E is a diagrammatic representation of the molecular structures 302of three thiol molecules that are involved in the synthesis of thelevoglucosan-based compounds, according to some embodiments of thepresent disclosure. The three thiol molecules are 3-mercaptopropionate352, 2-mercaptoethanol 356, and cysteamine hydrochloride (HCl) 360. Eachof these thiols can provide thioethers with a functional group (e.g.,carboxylic acid, hydroxyl, or amino functional groups) in the synthesisof E²-functionalized thioether-linked levoglucosan-based flame retardantcompounds. The syntheses and structures of the E²-functionalizedthioether-linked flame retardant levoglucosan-derived compounds arediscussed in greater detail with respect to FIG. 5F.

FIG. 4 is chemical reaction diagram illustrating processes 400-1 and400-2 of synthesizing a di-protected levoglucosan derivative 408 and amono-protected levoglucosan derivative 412, according to someembodiments of the present disclosure. In process 400-1, levoglucosan202 is reacted at approximately 60° C. with benzyl bromide (BnBr) andbarium oxide (BaO) in a dimethylformamide (DMF) solution. This reactionadds benzyl (Bn) protecting groups to the first and third positions onthe levoglucosan 202, leaving one unprotected hydroxyl group at thesecond position. The product of this reaction is referred to as adi-protected levoglucosan 408 herein.

In process 400-2, levoglucosan 202 is reacted with vinyl acetate in aregioselective reaction catalyzed by the lipase enzyme. This reactionattaches an acetyl (Ac) protecting group at the second position onlevoglucosan 202, producing a mono-protected levoglucosan 412.Subsequent reactions are carried out on levoglucosan 202 and the twoprotected levoglucosans 408 and 412 to form phenyl-substituted,monofunctionalized, difunctionalized, and trifunctionalizedlevoglucosan-based flame retardant compounds. These reactions arediscussed in greater detail with respect to FIGS. 5A-5F.

FIG. 5A is a chemical reaction diagram illustrating processes 500-1 and500-2 of forming an R¹-trifunctionalized levoglucosan-based flameretardant compound 504 and a phenyl-substituted levoglucosan-based flameretardant compound 508, according to some embodiments of the presentdisclosure. In both processes 500-1 and 500-2, levoglucosan 202 isreacted with a phosphorus-based flame retardant molecule 204 or 206,respectively, as well as catalytic dimethylaminopyridine (cat. DMAP),and/or a stoichiometric amount of an organic amine (e.g., triethylamine)in a dichloromethane (DCM) solution. The reactions attach FR moieties atthe hydroxyl groups on levoglucosan 202.

In process 500-1, the reaction is carried out with an R¹-functionalizedphosphorus-based compound 204, and allyl-306 or epoxy-307 functionalizedFR moieties are attached at the hydroxyl groups on levoglucosan 202.This reaction forms an R¹-trifunctionalized levoglucosan-based flameretardant compound 504. This compound 504 is a levoglucosan-based flameretardant compound that can be polymerized or act as a cross-linker inanother polymer. Its inclusion in a polymer, either by polymerization orcross-linking, causes the polymer to be flame retardant. Additionally,it should be noted that an epoxy R¹ group 307 on any of thefunctionalized levoglucosan-based flame retardant compounds disclosedherein can be produced by reacting an allyl functional group 306 with aperoxide reagent, such as meta-chloroperoxybenzoic acid (mCPBA).Further, epoxy R¹ groups 307 can ring-open in reactions involvingnucleophiles.

In process 500-2, the reaction is carried out with a phenyl-substitutedphosphorus-based compound 206. Phenyl-substituted FR moieties areattached at the hydroxyl groups on levoglucosan 202, and aphenyl-substituted levoglucosan-based flame retardant compound 508 isformed. This compound 508 is a levoglucosan-based flame retardant smallmolecule, which can be blended with a polymer to impart flameretardancy. Reactions with the phosphorus-based flame retardantcompounds 204 and 206, cat. DMAP in DCM, and/or a stoichiometric amountof an organic amine can attach FR moieties to unprotected hydroxylgroups on any of the levoglucosan compounds disclosed herein (e.g.,compounds 408 and 412). This is discussed in greater detail below.

FIG. 5B is a chemical reaction diagram illustrating processes 500-3 and500-4 of forming an R¹(2)-monofunctionalized levoglucosan-based flameretardant compound 512 and an R¹(1,3)-difunctionalizedlevoglucosan-based flame retardant compound 516, according to someembodiments of the present disclosure. The numbers in parentheses in thenames of the R¹(2)-monofunctionalized 512 and R¹(1,3)-difunctionalizedlevoglucosan-based flame retardant compound 516 indicate the position ofthe R¹ functional group. That is, “(2)” indicates that an R¹ functionalgroup is at the second position, and “(1,3)” indicates that R¹functional groups are at the first and third positions. Parentheticalnumbers are used in this way in naming each of the mono- ordifunctionalized levoglucosan-based flame retardant compounds disclosedherein.

In the first step of both processes 500-3 and 500-4, the di-protectedlevoglucosan 408 is reacted with a phosphorus-based flame retardantmolecule 204 or 206, respectively. The selected phosphorus-based flameretardant molecule 204 or 206 is reacted with the di-protectedlevoglucosan 408, catalytic dimethylaminopyridine (cat. DMAP) and/or astoichiometric amount of an organic amine (e.g., triethylamine) in adichloromethane (DCM) solution. These reaction conditions cause thephosphorus-based flame retardant molecule 204 or 206 to attach FRmoieties at the unprotected hydroxyl group on the di-protectedlevoglucosan 408. The intermediate products of the first and secondsteps in processes 500-3 and 500-4 are not shown.

In the second step in both processes 500-3 and 500-4, the Bn protectinggroups are removed in a deprotection reaction. In the deprotectionreaction, the Bn-protected products of the first steps are deprotectedby hydrogenolysis (e.g., a reaction with hydrogen (H₂) catalyzed bypalladium (Pd) in an ethanol solution). Removal of the benzyl (Bn) groupcan also be accomplished by reaction with an oxidizing agent (e.g.,chromium trioxide (CrO₃)/acetic acid, ozone, N-bromosuccinimide,N-iodosuccinimide, etc.) or a reducing agent such as Na/NH₃ or Li/NH₃.Additionally, this deprotection can be carried out via a Lewis acidreaction with trimethylsilyl iodide in dichloromethane.

In the third step in process 500-3, the deprotected compound is reactedwith a phenyl-substituted phosphorus-based flame retardant compound 206,cat. DMAP and/or a stoichiometric amount of an organic amine (e.g.,triethylamine) in a DCM solution. This reaction produces theR¹(2)-monofunctionalized levoglucosan-based flame retardant compound512. In the third step in process 500-4, the deprotected compound isreacted with an R¹-substituted phosphorus-based flame retardant compound204, cat. DMAP and/or a stoichiometric amount of an organic amine (e.g.,triethylamine) in a DCM solution. This reaction produces theR¹(1,3)-difunctionalized levoglucosan-based flame retardant compound516. The functionalized levoglucosan compounds 512 and 516 can bepolymerized to form a flame retardant polymer. Additionally, theR¹(1,3)-difunctionalized levoglucosan-based flame retardant compound 516can be added to a polymer as a cross-linker, and theR¹(2)-monofunctionalized levoglucosan-based flame retardant compound 512can be bound to polymer chains. Their inclusion in a polymer, either bypolymerization, cross-linking, or binding to single locations on thepolymer chain, causes the polymer to be flame retardant.

FIG. 5C is a chemical reaction diagram illustrating processes 500-5 and500-6 of forming an R¹(2,3)-difunctionalized levoglucosan-based flameretardant compound 520 and an R¹(1)-monofunctionalizedlevoglucosan-based flame retardant compound 524, according to someembodiments of the present disclosure. In the first step of bothprocesses 500-5 and 500-6, the mono-protected levoglucosan 412 isreacted with a phosphorus-based flame retardant molecule 204 or 206,respectively. The selected phosphorus-based flame retardant molecule 204or 206 is reacted with the mono-protected levoglucosan 412, catalyticdimethylaminopyridine (cat. DMAP) and/or a stoichiometric amount of anorganic amine (e.g., triethylamine) in a dichloromethane (DCM) solution.These reaction conditions cause the phosphorus-based flame retardantmolecule 204 or 206 to attach FR moieties to the unprotected hydroxylgroups at the second and third positions on the mono-protectedlevoglucosan 412. The intermediate products of the first and secondsteps in processes 500-5 and 500-6 are not shown.

In the second step in both processes 500-5 and 500-6, the acetyl (Ac)protecting group is removed in a deprotection reaction. In thedeprotection reaction, the Ac-protected products of the first steps arereacted with an acid in an ethanol solution. However, other deprotectionconditions can include an aqueous acid at approximately pH 2 or lower,an aqueous base at approximately pH 9 or higher, or an anhydrous base inmethanol. In the third step in process 500-3, the deprotected compoundis reacted with a phenyl-substituted phosphorus-based flame retardantcompound 206, cat. DMAP and/or a stoichiometric amount of an organicamine (e.g., triethylamine) in a DCM solution. This reaction producesthe R¹(2,3)-difunctionalized levoglucosan-based flame retardant compound520.

In the third step in process 500-4, the deprotected product of the firststep is reacted with an R¹-substituted phosphorus-based flame retardantcompound 204, cat. DMAP and/or a stoichiometric amount of an organicamine (e.g., triethylamine) in a DCM solution. This reaction producesthe R¹(1)-monofunctionalized levoglucosan-based flame retardant compound524. The functionalized levoglucosan compounds 520 and 524 can bepolymerized to form a flame retardant polymer. Additionally, theR¹(2,3)-difunctionalized levoglucosan-based flame retardant compound 520can be added to a polymer as a cross-linker, and theR¹(1)-monofunctionalized levoglucosan-based flame retardant compound 524can be bound to polymer chains. Their inclusion in a polymer, either bypolymerization, cross-linking, or binding to single locations on thepolymer chain, causes the polymer to be flame retardant.

FIG. 5D is a chemical reaction diagram illustrating a process 500-7 offorming an R²-trifunctionalized levoglucosan-based flame retardantcompound 528, according to some embodiments of the present disclosure.In this reaction the R¹-trifunctionalized levoglucosan-based flameretardant compound 504 having an epoxy R¹ group 307 is combined withlithium bromide (LiBr) in an appropriate solvent (e.g., methanol,ethanol, ether, acetone, etc.). Carbon dioxide (CO₂) is added to themixture, either by bubbling or by injecting into the headspace of aflask containing the mixture. The CO₂ reacts with the epoxy R¹ groups307 to form propylene carbonate R² groups 529, thereby producing anR²-trifunctionalized levoglucosan-based flame retardant compound 528.

Analogous LiBr/CO₂ reactions can be carried out with any of theepoxy-functionalized levoglucosan-based flame retardant compoundsdisclosed herein to form propylene carbonate (R² 529) mono- ordifunctionalized levoglucosan-based flame retardant compounds. Forexample, LiBr/CO₂ reactions with the R¹(2)-monofunctionalizedlevoglucosan-based flame retardant compound 512 and theR¹(1,3)-difunctionalized levoglucosan-based flame retardant compound 516produce an R²(2)-monofunctionalized levoglucosan-based flame retardantcompound and an R²(1,3)-difunctionalized levoglucosan-based flameretardant compound, respectively. Further, LiBr/CO₂ reactions with theR¹(2,3)-difunctionalized levoglucosan-based flame retardant compound 520and the R¹(1)-monofunctionalized levoglucosan-based flame retardantcompound 524 produce an R²(2,3)-difunctionalized levoglucosan-basedflame retardant compound and an R²(1)-monofunctionalizedlevoglucosan-based flame retardant compound, respectively. TheseR²-mono- and difunctionalized compounds are not illustrated herein.

The R²-mono-, di-, and trifunctionalized levoglucosan-based flameretardant compounds can be polymerized to form a flame retardantpolymer. Additionally, the R²-di- and trifunctionalizedlevoglucosan-based flame retardant compounds can be added to a polymeras a cross-linker, and the R²-monofunctionalized levoglucosan-basedflame retardant compounds can be bound to polymer chains. The inclusionof these R²-functionalized levoglucosan-based flame retardant compoundsin a polymer, either by polymerization, cross-linking, or binding tosingle locations on the polymer chain, causes the polymer to be flameretardant.

FIG. 5E is a chemical reaction diagram illustrating a process 500-8 offorming phenyl-substituted E¹ thioether-linked levoglucosan-based flameretardant compounds 532, according to some embodiments of the presentdisclosure. The phenyl-substituted thioether groups are referred to asE¹ groups 536, 540, or 544 herein, and are bound to FR moieties on thelevoglucosan-based flame retardant compounds 532. Process 500-8 can becarried out under reaction conditions A, B, or C. Each of these reactionconditions is a thiol-ene reaction between the R¹-trifunctionalizedlevoglucosan-based flame retardant compound 504 with allyl R¹ groups 306and a phenyl-substituted flame retardant thiol molecule 328, 336, or348. The syntheses and structures of the phenyl-substituted flameretardant thiol molecules are discussed in greater detail with regard toFIGS. 3C and 3D.

The thiol molecules react with allyl R¹ groups 306 on theR¹-trifunctionalized levoglucosan-based flame retardant compound 504.The phenyl-substituted E¹ thioether-linked flame retardantlevoglucosan-based compounds 532 are flame retardant small moleculesthat can be blended with polymers to impart flame retardancy. It shouldbe noted that the reactions can also be carried out with the mono- anddi-functionalized levoglucosan-based flame retardant compounds 512, 516,520, and 524 having allyl R¹ groups 306, resulting in analogous mono-and di-E¹ thioether-linked levoglucosan-based flame retardant compounds.

Under thiol-ene reaction conditions A, the R¹-trifunctionalizedlevoglucosan-based flame retardant compound 504 having allyl R¹ groups306 is reacted with the phenyl-substituted carboxylic acid-derivedphenyl-substituted flame retardant thiol molecule 328 under UV light ina methanol (MeOH) solution. The resulting phenyl-substituted E¹thioether-linked levoglucosan-based flame retardant compound 532 hasthioether E¹ groups 536 that correspond to the carboxylic acid-derivedphenyl-substituted flame retardant thiol molecule 328.

Under thiol-ene reaction conditions B, the R¹-trifunctionalizedlevoglucosan-based flame retardant compound 504 having allyl R¹ groups306 is reacted with the phenyl-substituted hydroxy-derivedphenyl-substituted flame retardant thiol molecule 336 under UV light.The resulting phenyl-substituted E¹ thioether-linked levoglucosan-basedflame retardant compound 532 has thioether E¹ groups 540 that correspondto the hydroxy-derived phenyl-substituted flame retardant thiol molecule336.

Under thiol-ene reaction conditions C, the R¹-trifunctionalizedlevoglucosan-based flame retardant compound 504 having allyl R¹ groups306 is reacted with the phenyl-substituted amine-derivedphenyl-substituted flame retardant thiol molecule 348 under UV light ina pH 9 methanol solution. The resulting phenyl-substituted E¹thioether-linked levoglucosan-based flame retardant compound 532 hasthioether E¹ groups 544 that correspond to the amine-derivedphenyl-substituted flame retardant thiol molecule 348.

FIG. 5F is a chemical reaction diagram illustrating a process 500-9 offorming trifunctionalized E² thioether-linked levoglucosan-based flameretardant compounds 548, according to some embodiments of the presentdisclosure. The functionalized thioether groups are referred to as E²groups 552, 556, and 560 herein, and are bound to FR moieties on thelevoglucosan-based flame retardant compounds 548. Process 500-9 can becarried out under reaction conditions A, B, or C. Each of these reactionconditions is a thiol-ene reaction between the R¹-trifunctionalizedlevoglucosan-based flame retardant compound 504 having allyl R¹ groups306 and a thiol molecule (3-mercaptopropionate 352, 2-mercaptoethanol356, or cysteamine hydrochloride (HCl) 360).

Each thiol molecule reacts with an allyl R¹ group 306 on theR¹-trifunctionalized levoglucosan-based flame retardant compound 504,forming E²-trifunctionalized levoglucosan- based compounds 548. Itshould be noted that the reactions can also be carried out with themono- and di-functionalized levoglucosan-based flame retardant compounds512, 516, 520, and 524 having allyl R¹ groups 306. Carrying press 500-9with an R¹-monofunctionalized 512 or 524 or R¹-difunctionalized 516 or520 levoglucosan-based flame retardant compound forms anE²-monofunctionalized or an E²-difunctionalized thioether-linkedlevoglucosan-based flame retardant compound, respectively. TheE²-tri-548, E²-di-, and E²-monofunctionalized thioether-linkedlevoglucosan-based flame retardant compounds can bind to polymers,and/or act as cross-linkers, causing the polymers to be flame retardant.

Under thiol-ene reaction conditions A, the R¹-trifunctionalizedlevoglucosan-based flame retardant compound 504 having allyl R¹ groups306 is reacted with 3-mercaptopropionate 352 under UV light in amethanol (MeOH) solution. The resulting E²-trifunctionalizedthioether-linked levoglucosan-based flame retardant compound 548 hascarboxylic acid-functionalized thioether E² groups 552 that correspondto the 3-mercaptopropionate 352. Under thiol-ene reaction conditions B,the R¹-trifunctionalized levoglucosan-based flame retardant compound 504having allyl R¹ groups 306 is reacted with 2-mercaptoethanol 356 underUV light. The resulting E²-trifunctionalized thioether-linked flameretardant levoglucosan-based compound 548 has hydroxyl-functionalizedthioether E² groups 556 that correspond to the 2-mercaptoethanol 356.Under thiol-ene reaction conditions C, the R¹-trifunctionalizedlevoglucosan-based flame retardant compound 504 having allyl R¹ groups306 is reacted with cysteamine HCl 360 under UV light in a pH 9 methanolsolution. The resulting E²-trifunctionalized thioether-linked flameretardant levoglucosan-based compound 548 has amine-functionalizedthioether groups 560 that correspond to the cysteamine HCl 360.

The processes of forming the levoglucosan-based flame retardantcompounds illustrated herein can be carried out with differentcombinations of phosphorus-based flame retardant molecules 204 and 206.In some embodiments, these processes can be carried out with either allphosphate-based flame retardant molecules (204-1 and/or 206-1) or allphosphonate-based flame retardant molecules (204-2 and/or 206-2). Inother embodiments, a mixture of both phosphate-phosphonate-based flameretardant molecules can be used. Carrying out these processes with amixture of phosphate- and phosphonate-based compounds (206-1/206-2and/or 204-1/204-2) can result in the production of levoglucosan-basedflame retardant monomers with both phosphoryl and phosphonyl FR groups.

However, in some instances, adding a mixture of phosphate- andphosphonate-based compounds (206-1/206-2 or 204-1/204-2) can result inthe production of levoglucosan-based flame retardant monomers with allphosphoryl or all phosphonyl FR moieties. Additionally, adding a mixtureof phosphate- and phosphonate-based compounds (206-1/206-2 or204-1/204-2) to the reaction can yield a mixture of products thatincludes some combination of levoglucosan-based flame retardant monomerswith either all phosphoryl or all phosphonyl FR groups andlevoglucosan-based flame retardant monomers with both phosphoryl andphosphonyl FR groups.

FIG. 6 is a diagrammatic representation 600 of a genericlevoglucosan-based flame retardant compound 604. The genericlevoglucosan-based flame retardant compound 604 can represent any of thelevoglucosan-based flame retardant compounds disclosed herein. Thefirst, second, and third positions on the levoglucosan-based flameretardant compound 604 have M¹, M², and M³ groups, respectively. Each Mgroup can be either a phenyl-FR moiety 608-1, an R-FR moiety 608-2, oran E-FR moiety 608-3. The R groups on the R-FR moieties 608-2 are eitherR¹ (allyl 306 or epoxy 307) or R² (propylene carbonate 529) groups, andthe E groups on the E-FR moieties 608-3 are either phenyl-substituted E¹thioether groups 536, 540, or 544 or functionalized E² thioether groups552, 556, or 560. The synthesis and structures of compounds representedby the generic structure 604 are discussed in greater detail withrespect to FIGS. 5A-5F.

FIG. 7A is a diagrammatic representation of the structures 700 ofgeneric R¹- or R²-functionalized levoglucosan-based flame retardantmonomers 704, 708, and 712, according to some embodiments of the presentdisclosure. In FIG. 7A, R¹ (allyl 306 or epoxy 307) and R² (propylenecarbonate 529) are referred to as “R” for simplicity. The monomers areR-trifunctionalized levoglucosan-based flame retardant compounds 704(e.g., compounds 504 and 528), R-difunctionalized levoglucosan-basedflame retardant compounds 708 (e.g., compounds 516 and 520), andR-monofunctionalized levoglucosan-based flame retardant compounds 712(e.g., compounds 512 and 524). The R-functionalized levoglucosan-basedcompounds 704, 708, and 712 are polymerized to form levoglucosan-basedflame retardant polymers. For simplicity, each structure in FIG. 7Ashows only ligands with R functional groups (allyl 306, epoxy 307, orpropylene carbonate 529). An oval labeled “L” represents thelevoglucosan core of each monomer.

FIG. 7B is a chemical reaction diagram illustrating processes 714-1,714-2, and 714-3 of synthesizing levoglucosan-based flame retardantpolymers 716, 720, and 724 from levoglucosan-based flame retardantcompounds 708, according to some embodiments of the present disclosure.The reactions illustrated herein are examples of polymers that can besynthesized from the levoglucosan-based flame retardant compounds, butother polymers can be produced as well (e.g., by changing reactionconditions, co-monomers, R groups, etc.).

Processes 714-1-714-3 illustrate the polymerization ofR-difunctionalized levoglucosan-based flame retardant monomers 708 only.However, it should be noted that each of these polymerization reactionscan also be carried out with the R-trifunctionalized levoglucosan-basedflame retardant compounds 704. Additionally, processes 714-1 and 714-3can be carried out with the R-monofunctionalized levoglucosan-basedflame retardant compounds 712. Further, in some embodiments, thepolymerization reactions are carried out with a combination of bothR-difunctionalized levoglucosan-based flame retardant compounds 708 andR-trifunctionalized levoglucosan-based flame retardant compounds 704,both R-difunctionalized levoglucosan-based flame retardant compounds 708and R-monofunctionalized levoglucosan-based flame retardant compounds712, both R-trifunctionalized levoglucosan-based flame retardantcompounds 704 and R-monofunctionalized levoglucosan-based flameretardant compounds 712, or a combination of monomers that includestri-, di-, and monofunctionalized monomers in any ratio.

In process 714-1, allyl-derived levoglucosan-based flame retardantpolymers 716 are formed from R¹-difunctionalized levoglucosan-basedflame retardant compound 708 having allyl R¹ groups 306. TheR¹-difunctionalized levoglucosan-based flame retardant compound 708 isreacted with a Ziegler-Natta catalyst. Ziegler-Natta catalysts catalyzethe polymerization of 1-alkenes. Examples of these catalysts can includeheterogeneous Ziegler-Natta catalysts based on titanium compounds andhomogeneous Ziegler-Natta catalysts based on complexes of titanium,zirconium, or hafnium. Heterogeneous and homogeneous Ziegler-Nattacatalysts can be used in combination with organoaluminum co-catalysts insome embodiments.

In process 714-2, epoxy-derived levoglucosan-based flame retardantpolymers 720 are formed from R¹-difunctionalized levoglucosan-basedflame retardant compound 708 having epoxy R¹ groups 307. ThisR¹-difunctionalized levoglucosan-based flame retardant compound 708 isreacted with a base and a second monomer 706. The second monomer 706 isa compound with at least two hydroxyl (—OH) groups or at least two amino(—NH₂) groups (e.g., a diol, polyol, diamine, polyamine, etc.) Thiscompound 706 is illustrated as a gray oval with attached A groups. The Agroups represent hydroxyl groups or an amino groups. It should be notedthat, while two A groups are illustrated herein, there are more than twoA groups in some embodiments. Additionally, in some embodiments, theR-difunctionalized levoglucosan-based compound 708 having epoxy R¹groups 307 self-polymerizes under basic conditions. In these instances,the reaction does not include the second monomer 706.

In process 714-3, propylene carbonate-derived levoglucosan-based flameretardant polymers 724 are formed from R²-difunctionalizedlevoglucosan-based flame retardant compounds 708 having propylenecarbonate R² groups 529. The R²-difunctionalized levoglucosan-basedflame retardant monomer 708 is reacted in a ring-opening polymerizationinitiated by a base. Examples of bases that can be used as initiatorscan include potassium hydroxide (KOH), sodium hydroxide (NaOH), lithiumhydroxide (LiOH), 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU),triazabicyclodecene (TBD), etc.

In addition to the polymers illustrated in FIG. 7B, thelevoglucosan-based flame retardant compounds disclosed herein can beused in the synthesis of other flame retardant polymers in someembodiments. An array of classes of flame retardant polymers can be madewith different combinations of monomers. These polymerization processesare in accordance with polymer chemistry platforms that can includepolyhydroxyurethanes, polycarbonates, polymers obtained by radicalpolymerization, polyurethanes, polyesters, polyacrylates, epoxy resins,polyimides, polyureas, polyamides, poly(vinyl-esters), etc.

One example of an application of polymers that incorporatelevoglucosan-based flame retardant compounds is in plastics used inelectronics hardware, such as integrated circuit packages. Additionalapplications can include acoustic dampening, cushioning, plastics,synthetic fibers, insulation, etc. The levoglucosan-based flameretardant compounds can also be used to make adhesives such asbio-adhesives, elastomers, thermoplastics, emulsions, thermosets, etc.Further, materials containing the levoglucosan-based flame retardantcompounds can be incorporated into various devices with electroniccomponents that can include printed circuit boards (PCBs),semiconductors, transistors, optoelectronics, capacitors, resistors,chip carriers, etc.

Resins for printed circuit boards (PCBs) can be made flame retardant byincorporating polymers that include levoglucosan-based flame retardantcompounds. PCBs are electrical circuits that can be found in most typesof electronic device, and they support and electronically connectelectrical components in the device. PCBs are formed by etching a copperconductive layer laminated onto an insulating substrate. The insulatingsubstrate can be a laminate comprising a resin and a fiber. Many resinsin PCBs contain a polymer, such as an epoxy, a polyhydroxyurethane, apolycarbonate, a polyester, a polyacrylate, a polyimide, a polyamide, apolyurea, a poly(vinyl-ester), etc. Using polymers that incorporate thelevoglucosan-based flame retardant compounds can prevent the PCB fromcatching fire when exposed to high temperature environments orelectrical power overloads.

It should be noted that, in some embodiments, the compounds describedherein can contain one or more chiral centers. These can include racemicmixtures, diastereomers, enantiomers, and mixtures containing one ormore stereoisomer. Further, the disclosed compounds can encompassracemic forms of the compounds in addition to individual stereoisomers,as well as mixtures containing any of these.

The synthetic processes discussed herein and their accompanying drawingsare not to be construed as limiting. One skilled in the art wouldrecognize that a variety of synthetic reactions may be used that vary inreaction conditions, components, methods, etc., which ultimatelygenerate one or both of levoglucosan-based flame retardant compounds andtheir corresponding polymer derivatives. In addition, the reactionconditions can optionally be changed over the course of a process.Further, in some embodiments, processes can be added or omitted whilestill remaining within the scope of the disclosure, as will beunderstood by a person of ordinary skill in the art.

What is claimed is:
 1. A levoglucosan-based flame retardant compoundwith a formula of:

wherein M¹, M², and M³ are phosphorus-based flame retardant groups, andwherein at least one of the phosphorus-based flame retardant groupsincludes a phenyl substituent.
 2. The levoglucosan-based flame retardantcompound of claim 1, wherein at least one of the phosphorus-based flameretardant groups is a functionalized flame retardant group.
 3. Thelevoglucosan-based flame retardant compound of claim 2, wherein thefunctionalized flame retardant group has a functional group selectedfrom a group consisting of an allyl group, an epoxy group, and apropylene carbonate group.
 4. The levoglucosan-based flame retardantcompound of claim 2, wherein the functionalized flame retardant grouphas a functional group selected from a group consisting of an aminogroup, a carboxylic acid group, and a hydroxyl group.
 5. Thelevoglucosan-based flame retardant compound of claim 1, wherein the atleast one of the phosphorus-based flame retardant groups having thephenyl substituent includes an additional phenyl substituent.
 6. Thelevoglucosan-based flame retardant compound of claim 1, wherein at leastone of the phosphorus-based flame retardant groups has a phosphorylmoiety with a formula of:

wherein Ph is phenyl.
 7. The levoglucosan-based flame retardant compoundof claim 1, wherein at least one of the phosphorus-based flame retardantgroups has a phosphonyl moiety with a formula of:

wherein Ph is phenyl.
 8. The levoglucosan-based flame retardant compoundof claim 1, wherein the functionalized flame retardant group has afunctional group selected from a group consisting of a carboxylic acidgroup, a hydroxyl group, and an amine group.
 9. A process of forming alevoglucosan-based flame retardant polymer, comprising: providinglevoglucosan; providing a phosphorus-based flame retardant moleculehaving at least one phosphoryl moiety with a formula selected from thegroup consisting of:

 wherein Ph is phenyl; and incorporating the levoglucosan-based flameretardant compound into a polymer by covalent binding to form thelevoglucosan-based flame retardant polymer.
 10. The process of claim 9,wherein the levoglucosan is obtained from a bio-based source.
 11. Theprocess of claim 9, wherein the levoglucosan-based flame retardantcompound is incorporated into the polymer by cross-linking.
 12. Theprocess of claim 9, wherein the levoglucosan-based flame retardantcompound is incorporated into the polymer by a polymerization reaction.13. The process of claim 12, wherein the polymerization reactionincludes at least one additional monomer.
 14. The process of claim 9,wherein the levoglucosan-based flame retardant compound has at least onefunctional group selected from a group consisting of an allyl group, anepoxy group, a propylene carbonate group, a carboxylic acid group, anamine group, and a hydroxyl group.
 15. The process of claim 9, whereinone or more protecting groups are bound to the levoglucosan.
 16. Anarticle of manufacture, comprising a material containing a polymer intowhich a levoglucosan-based flame retardant compound has beenincorporated, the levoglucosan-based flame retardant compound having theformula:

wherein M¹, M², and M³ are phosphorus-based flame retardant groups, andwherein at least one of the phosphorus-based flame retardant groupsincludes a phenyl substituent.
 17. The article of manufacture of claim16, further comprising an electronic component.
 18. The article ofmanufacture of claim 16, wherein the material is a plastic forintegrated circuit packaging.
 19. The article of manufacture of claim16, wherein the material is an adhesive.